Internal combustion engine



Sept. 11, 1928. 1,684,293 I w. ALLAN INTERNAL COMBUS TION ENGINE Filed March 5, 192'? 2 SheetsSheet 1 g 16 Mme/Mm: W Mum Jun/v W. ALLAN INTERNAL COMBUSTION ENGINE Sept. 11, 1928.

' each revolution would be produced,

The inyention also comprises other tea- Patented Sept. 11, 1928;

' UNITED STATES WILLIAM ALLAN, or names, SCOTLAND.

' INTERNAL-COMBUSTION ENGINE. i

; Application filed March a, 1927, Serial No.

This inventionVrelat-es to internal coinbustion engines of what are known as the two stroke type, and embodies a novel construction the principal feature of which'is that the power stroke is divided between a nor,- mally reciprocating pistonand a reciprocat ing working cylinder in which said piston operates, whereby air for scavenging and the mixture constituting the charge are precompressed and'ports are controlled to admit air andm'ixture to preconipression cyhnders:

to exhaust the products of combustion, and to transfer the 'pre'c'ompress'ed air and mixture.

to the working cylinder." i v Perfect balance may be ensured as regards reciprocatingmasses by (varying the relative;

or proportionate strokes of the piston and. lBClPlOCilftlllg WOI lZIIIg CyllIIClGI;

The invention can :be applied to vertical,"

horizontal, inclined or radial engines, either may, with advantage be applied with cylins de'rs in tandem, or opposedarrangement, with a eommoncrankshatt between them, in which case two balanced" power impulses tufresot construction, arrangement and combination of parts, all'as hereinafter fully def scribed, and specifically pointed outin the ference being-ma den to the a-ppende'd cla'inis, r accompanying drawings which show two embodiments of the invention, thefirst compr sin' an engine having cylinders'in tandem or opposed arrangement and the'second ai single cylinder neg-zine.

In thesed rawin'gs Fig.- 1, isa central -vertica'l section of the first embodiment and Fig.

Qis another centralfverticalsection in plane at right angles to Fig-.1. Figs. are cross sections on lines 3+3, 4- l,- 5'5, "66, re-

sp'ectiv'elyof Figs. 2' and Fig. 7 isa vertical central section otthe alternative embodiment v referred to above; 2

To first refer to "the construction of Figs;

" 1-6 the engine shown comprises an outer sta=- tion'ary cylinder 1 which is water-j acketed, as at 2 with inlets and outlets for the c rcusages 5' and ports in its wall as hereinafter described. Within saidstationary cylinder;

1 are two reciprocating working cylinders )6 also provided with ports hereinafter. de-

scribed, and within each of said reciprocat ing cylinder operates an ordinaiyworking' of scavenging air to the inner or 172,445, and in Great Britain October 6, 11926;

piston? connectedby a piston rod8 to a common crank shaft 9 suitably with interposed rollerbea-rings 10, this crank shaft-being mounted in bearings'll carried in the walls or the outer-stationary cylinder 1 and the space between the two opposed working cyla inders constituting-a crank case 12. H

The crank case end or each reciprocating working cylinder 6 is increased in area: as by threading thereon a disc ldadapted to slide on a machined race on the inside of the outer cylinder '1, -by' beingconnected. to the crank shaft by means of rods 13 suitably With-interposed roller bearings 13, and forming a stepped or truncz'ited pumping or precompression. piston. The opposite or head end or each.reciprocating working cylinder 6 is also shaped orv formed a pumping or precompressioi i piston as by providing it at its outer end with a threaded bush 1 i of the single or -inulti=cylinder class and screwed in frointhefinterior. The cylin--- der end thus'rori-ned' in conjnnctionwith head'15 bolted to the end of the station-' ary cylinder 1 constitute a preconipression; chamber 116 andthe piston 18 at the crank case endconstitutes another precoinp'ression chamber 17 the capacity oithese chamhers-being controlled by their respective pistons 1a and 13 a 'ndeach chamberbeing connectable tothe interior of the reci-procat ing workingkcylinder by means of transfer passages'and ports- Either or both of said compression chambers can be used for the compression or thecharge or scavenging air and the reciprocating cylinder acts as a sleeve valve and controls said ports in man ner or phase hereinafter described starting);

from the head 15 or outer end or the cyliiider, namely, inlet of charge ;to the outeror head compression chamber-16, transfer or.

charge and scavenging air from the compres sion chamber 16,17 to the working cylinder 6, exhaust or gases from the latter and inlet base'coni 'pression chamber'17. I

To nowdescribethe port arrangementfid designates the induction forthe charge as from a carburetter as usual, and, which comniunicates with a seriesofannular inlet ports 19 (see also Fig. 3) in the outer end of the fixed cylinder 1 and leading totho head com A pressionchamber 16, this latter chamber bev incgprovided with a mixture transfer passage" 20 adapted during the operation of the engine to convey the mixture to :the combustionspace 21 of thereciprocating working eylin-- dcr 6 through transfer inlet ports 22 (see also 7 Fig. 4). The outer end of the fixed cylinder,

'1 isalso provided with a series of scavenging -air ports 23 which are adapted to communicats with the transfer passage 5 leading to the base compression chamber 17 Thereciprocating working cylinder 6 is provided 7 i with inletports 24 and-23. (see also. Fig. 4)

adapted to communicate during the opera t-ion'of the engine with the transfer inlet ports 22 andthe scavenging-air inlet ports 23 respectively. Finally at this end, the outer cylinder 1 is apertured for the reception of diametrically opposed ignition V plugs 25 adapted during the operation of the engine to communicate with the combustion space2l of the working cylinder through ports 26 in the wall of the latter (see also Fig. 5). By this construction it will be seen that the. ignition ports are protected or shrouded during a large portion of the working stroke.

At the base or crankcase end the outer cyl- 'incler 1 is provided with a series of exhaust ports 27 adaptedto communicate during the operation with other exhaust ports 28 in the wall of the working cylinder 6 and. communicating with a common exhaust manifold 29 (see also Fig.- .6). The saidexhaust ports 28 i I also however serve as inletportsfor scavengr exhaust ports 28 ing air from the crankcase 12 to the inner 2 at the upper ends of Figs. 1 and 2, that the parts are in position when the explosionof the chargetakes place, the piston 7 is at the inner or top end of its stroke, and the recipro eating cylinder is at the outer or lower end of its stroke, the said piston and cylinder always moving in opposite directions. 1

.The ports 19 communicatingwith the head compression chamber 16 and the ports 28 communicating with base compression chamher 17 areopen allowing air to pass from the crank chamber 13 to said compression, cham-.

ber 17 and the chargefrom the induction 18 to the head compression chamber 16. Under .[force of explosion the piston 7 moves out- Wards andthe reciprocating cylinder in-y wards, during which movement the piston disc 13 compresses air in chamber 17 and the bush 14 compresses the charge in chamber 16.

Atthe end of the power stroke the combined movement of cylinder .6 and piston 7 causes theparts to assume the positions shown at thc'lower end ofFigs. 1 and 2 in which the ports 27, 28 are opened for the exhaust of V burnt gases and the movement of the cylinder alone opens the scavenging air ports 23, 23

ind the mixtureinlet ports 22, 24at the head "to Figsrl to 6.

The work ng and precompressionportions' e made are cooled to a considerable self-starter.

be used for force-feed of .fuel and supply. of

or outer end of-the working cylinder; but allthese ports are so proportioned" that they are opened in the following sequence, namely, first exhaust, followed by scavenging and finally admission of mixture. 7

On the returnstroke the combined movements of piston 7 and reciprocating cylinder 6 compress a new charge admitted to chamber 16 and the movement of the cylinder alone creates depression inthe compression chamberg until the relative ports are againv opened topermit inlet of scavenging air and charge.

Inthe second or alternativelembodiment illustrated inFig. 7 the same general arrangement andconstruction is observed but the" charge is transferred to the working cylinder. 1

only through ports 30, 30 at the outer end or heads of the working and stationary cylinders respectively and the exhaust from the to takes placethrough ports 31,32 respectiveresponding parts to those used with reference of thereciprocating cylinder .6 may of any desired capacity and the relative speedsxof the piston and said c linder ma be such or be so controlledastoo 'tain the highestefiiciency, -for. example the ports at .the

"crankcase or lower end of the cylinder may be opened at the full combinedspeed of the piston and reciprocating cylinder and'the.

ports at the OUtBIyOl' top end at the speed of the reciprocating cylinderonly, or by ofl:'- setting or suitably arranging the crankshaft the'lports at either end of the working cylinder may be caused to open and close in any re quired relation to each other. i 1

The compression ratio. of thegcharge -.61+-

so cylinder and transfer of scavenging air there- 1y at the crank case end. .In this figure the V rcniamingreference characters deslgnate corhead compression chamber may also be variable for instance by extending thebore of the' stationarycylinder and providing it with anadjustable plug, plunger or equivalent 0perated ior-example-in conjunction with the main throttle valve wherebythe ratio may be increased as the throttle is "opened,

It will also be apparent from the above description that the precompression of {the charge and air andthe control of the'ports is effected without complicated internalmechanism. Surplus. of air compressed .in

the base or inner chamber may be available foroperating the brakes, horn, windscreenwiperor signalling devices or for inflating the tiresof a motor vehicle with which such an engine maybe used and if used in con.-

junction with a reservoir also for operating :1 Such compressed air might also lubricant to difierent parts of theengine and chassis thus permitting a lubricant pump to be dispensed with. i

What I claim as my inventionand desire to secure by Letters Patent of the United States stationary cylinder, having a pumping mem her working in said inner compression chamber, and having a head at its outer end, a piston in said piston cylinder, and means connecting said piston cylinder and said piston respectively to said shaft, for imparting rotation to said shaft by reciprocation in opposite directions, said stationary cylinder having transfer ducts, and said cylinders having ports controlled by movements-of said piston cylinder and piston respectively, whereby while said piston cylinder is moving towards said shaft air is admitted to said inner com-- pression chamber and combustible mixture is admitted to the outer compression chamber, andwhile said piston cylinder is moving towards said outer compression chamber said mixture and said air are compressed, and ports are opened for exhaust from the space between said'piston and the head of said pistoncylinder, and the compressed air is adxmitted to said space, and then the compressed mixture is admitted to said space.

2. The combination claimed in claim 1, the

piston cylinder having for the admission of air'to theinner compression chamber ports which serve also as ports for exhaust from V the space between the piston and head of said piston cylinder.

In witness whereof I have signed this speci fication.

WILLIAM ALLAN. 

